A congressional aide placing a placard on a podium for House Republicans' legislation to overhaul the tax code.Thomson Reuters

Both the House and the Senate have passed a version of a tax plan with huge cuts for business taxes.

Credit Suisse crunched the numbers to see who would be paying the highest effective tax rate under proposed rules.

No matter which tax bill, whether from the House of Representatives or the Senate, eventually gets signed into law by President Donald Trump, taxes are likely to shrink for a wide swath of American companies.

Credit Suisse crunched the numbers based on the publicly available information about the plans to see which companies could end up paying the highest effective tax rate.

"Companies with primarily domestic end-markets tend to pay more in taxes," the bank said. "As a result, groups such as Retail, Transports, Business Services, and Telecom should outperform as investors begin to discount tax relief. This should come at the expense of TECH+, Pharma & Biotech, and Autos, which are disadvantaged by proposed changes."

Transports, discretionary retailers, and business services will carry the highest tax rates, according to Credit Suisse, with tech hardware and semiconductors most likely paying the lowest. The S&P 500, on average, will pay an effective tax rate of about 27.4%.

Here are the 12 companies that could pay the highest effective tax rates under the proposed rules: